Monday, 22 August 2016

Among the oldest feats of civilisation, and indeed of Human society in general, is the construction of cities. From the stone and wood of the ancient world, to the sprawling glass and steel of today, cities have always been at the heart of a civilisation's economic and political power, a nexus of wealth and culture. There are exceptions of course; the nomadic hordes of Genghis Khan for one, and many nomadic tribes of Africa. As a rule though it has been the city building cultures that lasted longest, and grew the largest.

There is a solid reason for this to be the case. With people gathered into larger communities it is increasingly easy to support people who are not directly engaged in the production of food and other basic necessities. These people, freed from the daily struggle for survival are freed to work on other things, such as developing better building techniques, better tools, or new medicines. There are also economic advantages to cities as hubs of commerce, and advantages of security that high walls and a large force of arms can provide. Beyond these concrete benefits are those of culture and of art, accelerated and fertilised by the proximity of thinkers who can afford to think instead of working in the fields.

While some of these advantages have been left in the past, the economics and cultural attraction of cities remain. Even if for no other reason than the basic Human desire for companionship cities will always be a part of Human existence. Or will they? Many SF settings include technology that would make cities less advantageous, and that even might even create conditions under which cities are no longer advantageous.

And so I get to the recently released game No Man's Sky, and the concept of a post scarcity world. Wikipedia has a pretty good look at the concept, so I won't go deep into it here. Wikipedia uses this definition;

Post-scarcity is a theoretical economy in which most goods can be produced in great abundance with minimal human labor needed, so that they become available to all very cheaply or even freely. Post-scarcity is not generally taken to mean that scarcity has been eliminated for all consumer goods and services; instead, it is often taken to mean that all people can easily have their basic survival needs met along with some significant proportion of their desires for goods and services, with writers on the topic often emphasising that certain commodities are likely to remain scarce in a post-scarcity society.

Many SF settings demonstrate technologies needed for a post scarcity world; advanced manufacturing, highly efficient food production, and access either to enough resources or advanced enough recycling that raw materials never become a concern. Strongly enough, though, few writers seem to take into consideration the impact such technologies would have on the world. There are, broadly speaking, two kinds of post scarcity. There is the more 'realistic' kind likely to be achieved at some point in a our own future, and the less feasible, more extreme example that science fiction occasionally portrays. The more realistic approach can result in a world that while markedly different, still retains the basic political and societal structure that it does today, including things like cities. The latter could result in far more drastic changes.

If large fusion reactors became plausible in the near future this will be a large step toward a post scarcity; the energy excess allowing extensive recycling and otherwise inefficient manufacturing techniques. And 3D printers, while they might eventually move manufacturing out of factories into the home, will still need power. Because such fusion power plants are likely to be hugely expensive and complexed they will be built to serve existing cities, which will then gain an advantage over rural areas that do not support a population large enough to warrant a reactor of their own. This basic argument applies to other technologies that right enable a post scarcity world; it they require large coordinated efforts from a government or similar organisation, then cities remain a valid part of human society.

But take a SF setting like No Man's Sky. In-universe it is possible to harvest elements through a handheld device, and a small spacecraft can carry the facilities needed to turn these elements into technology. If we assume that this technology is a kind of 'replicator' similar to what Star Trek uses is behind this portable manufacturing, and we assume that it can also be used to produce food from the correct raw materials, we have the perfect post scarcity. A single person could theoretically support their own existence without aid from any other individual, and at a level significantly above survival.

In No Man's Sky the megacities and space habitats common to many similar settings are conspicuous by their absence. Instead their are space stations and trading posts that seem to act mostly as hubs of commerce, and fleets of large ships. And this is in fact a highly logical outcome of the technology in the game. There is no reason for cities because they cannot offer any major advantage to those who live in them. Indeed, even the concept of nations and other political entities becomes less certain in such a setting.

If the technology of No Man's Sky was to be introduced into our world cities would not vanish overnight; and might never make a complete disappearance. Because a single person, and by extension a group of almost any size, can support itself without outside aid, there is nothing to prevent those who disagree with their parent society from beaching off and forming colonies of like minded people. In the past it was possible for people to load up a ship and sail across and ocean to colonise another land because they could take almost all their technology base with them. And if this becomes possible again it will happen.

While existing cities will likely remain as hubs of culture, knowledge, and history the formation of new cities or nations seems unlikely. If people are banding together purely because they want to be surrounded by people that they agree with, or share goals with, such groups do not have the incentive to grow larger than the point where it is still possible for everyone to know everyone else. That is not to say that it won't happen, but it will see far more common to see smaller groups. Perhaps communities akin to medieval monasteries or convents will arise; communities dedicated to a goal single goal. It might not be religious in nature, it could be the terraforming of a planet, or the building of a Matryoshka Brain.

These communities could take on various shapes. They could be small bases on planets, space stations, or starships. 'Nomad fleets' of starships might be ideal, able to find new resources on demand, and safer from hostile forces than a stationary colony would be. They would travel slowly about the galaxy, avoiding those that disagreed with them, and meeting up with others that did. With physical comfort taken care of by their technology art and entertainment could become the mainstay of commerce, and the fragmentation of culture into smaller, more variant groups would increase the diversity that those who looked for it could find.

In terms of politics it is interesting to note that while war is one of the most compelling reasons for political bodies to exist after a post scarcity has come about, the chances of war are much less. If people can leave their nation and settle somewhere else without becoming refugees dependant on the goodwill of others, they are unlikely to support a war that their leaders have started. Of course wars that the population does support will exist, based on conflict between variant cultures, but wars of economic or political convenience will be much less likely.

It is worth pointing out that the separation between what exists in the No Man's Sky universe and what might become reality in our own is a spectrum, not a vase of two discreet options. It is the details and exact scale of the technology that will determine the size of the groups that form, and how far they spread. If restricted to Earth the spread will be much smaller than if the whole galaxy is opened up by FTL travel. Micro-nations are a plausible middle ground, with the practical advantages of a political entity, and the freedom of a smaller group.

So while there is considerable debate over No Man's Sky as a game(I haven't played it myself), it is interesting as an example of one possible future rarely explored in SF, despite being well within the limits of common fictional technologies. While many SF settings unthinkingly reuse the tropes of other works, creating huge sprawling cities and urbanised planets, it would be good to see more variety; diverse nomadic societies rather than an unimaginative ecumenopolis.

Thursday, 21 July 2016

All that Glitters is not Gold One of the biggest problems in creating a SF story in any medium is the concessions that have to be made to the medium in which the story is told. This is especially prevalent in visual media such as movies, games, and comics/animation. The problem is acerbated for those how prefer SF that falls onto the 'harder' end of the spectrum, as they lose many inaccuracies usually used because they make the telling of the story easier. While someone unconcerned with how a space battle might actually look given the technology concerned it is a simple matter to add some glory lasers and explosions, copying what has worked in other franchises like Star Wars or Star Trek. For those of you that do worry over these details, read on..

I'm going to discuss some of the more common elements of space battles in visual SF, although by no means all of them. For each I'll try to look at why they are shown the way they are, why they are inaccurate, and how they can be changed for greater realism. A lost of this sort of thing comes down to the exact details of the setting so I will focus on fairly broad issues, things that are unlikely or impossible given our current understanding of physics.

Who, What, When, Where, Why? While you might think that a discussion of physics or technology would be the most important part of this blogpost, there are other aspects to creating a space battle equally important. If the battle is part of a story then it has to show the story or it is ultimately pointless.

Say you are producing something along the lines of Star Wars or Battlestar Galactica with main characters who fly fighters, and with a story that focuses on the personal element that they bring into the tale, rather than the grand strategy of admirals and kings. In this situation frantic dogfights with wheeling fighters, explosions, and hair-raising manoeuvres will probably serve the story quite well.

If, on the other hand, your story is about a nation, a war, or a leader rather than a simple soldier it has different requirements. Tactics will let you explore the leader's abilities, strategy will convey the importance of certain actions or individuals in the grand scheme of things. In this case your might want to set your scene on the bridge of a starship, with huge tactical displays, and hasty conferences between the officers.

The answers to the above questions will help you to decide on the details of your setting that facilitate the decision; things like the technology used, the strategies and goals, etc. Only then can you begin to work on the visual aspects of the space battle and know that it will support and compliment the story you are trying to tell, rather than distracting the viewer from it.

The two examples I gave are by no means the only choices, and you can even switch between the two within the course of a single battle. There are also other similar considerations; the design or a ship can be used to reflect on the nature of those who built them. Dull colours and blocky shapes can suggest lower level technology when contrasted with organic curves and polished metal. The scenario can also be expanded visually; chaotic formations during an ambush, or elegant fleet manoeuvres during the siege of a planet.

Space is Big
Space is called Space for a reason, mostly because there is a lot of it. Yet in a almost any work of visual SF - Star Wars, Star Trek, Farscape, Babylon 5, etc. - ships huddle together as though running out of space; as they are, in a way. The situation is even more ludicrous when you delve into the lore of the various settings and find out that the weapons involved are apparently capable of engaging the enemy at beyond visual rages. In anything remotely 'realistic' this is an almost inexcusable error. The reason it is so widespread is quite simple; screens have only so much space. To show a fleet or a battle in as exciting a way as possible, or to convey the course of a battle, the artist needs to crowd the spacecraft together.

Fortunately the cure is almost as simple as the explanation. The first is a technique occasionally used in Babylon 5; it involves showing one ship firing, and then cutting to its target and showing the impact of its weapons. Having a planet or other large astronomical feature in the background can help to give a sense of the distance between the opposing spacecraft, and if visible energy weapons are being used colour can differentiate between enemy and friendly fire. The second technique, and the one that better conveys a fleet, is to frequently show the tactical displays being used by the officers directing the battle. Since such a display should be designed to provide information in a clear manner it should not be too hard to make it legible to the audience. It also has the advantage that the display can be used to show planned manoeuvres before they are carried out.

Visible Drive Trails & Weapons Fire
Whenever missiles are used in visual media they are almost always have a neat trail of smoke or vapour to mark their progress, something occasionally produced by manned craft as well. Likewise energy weapons will glow brightly in all the colours of the rainbow, and even kinetic rounds will glow brightly. Once again the reasoning behind this is simple, it makes it easy to see what is happening and it looks cool. Movies and games both use this tactic, games often going on to give fighters long exhaust trails that make their trajectory say to determine visually. The Homeworld strategy games are notable in this regard with most small ships producing visible trails.

Glowing kinetic rounds, while they may seem the most unlikely, are in fact the most realistic - to an extent. Gauss cannon or railguns could heat up the projectile they are firing; simple iron shots might be glowing red or white hot by the time they leave the barrel. But while they might emit some light it is likely to be so little that combined with the small size and high speed of the projectiles they would be invisible to the human eye.

Missiles with smoke trails also seem to be quite plausible at first. Aircraft can leave contrails behind them, and chemical fuelled rockets will most likely produce some smoke, although it is minimised in missiles to make them harder to spot with the Mk.1 Eyeball. In space however a vapour or smoke trail will never form; with no air to slow and support particulate matter from the rocket engine the trail will disperse far to fast for the human eye to catch.

Energy weapons glowing seems like a pretty rational thing. They are after all composed of energy and in the case of plasma weapons are utilising a state of matter that does usually glow. Lasers will not be visible without particles to scatter the beam, the only reason that we can see them on Earth. The component particles of a particle beam do not emit energy unless they are slowed or deflected, and when this does occur the radiation emitted is probably not going to be visible given the energies involved. Plasma weapons might be visible as glowing projectiles, if they ever prove to be feasible in the first place; but given the tennis nature of fusion plasmas, and the relatively small volume of a plasma bolt, they might be very hard to see even then. The weapons that will be very visible would be things like nuclear shaped charges, although they would also be very brief.

Aside from the fact that this means space battles will never look like how Hollywood thinks they will there are a few other result of this. You will almost never see incoming fire. In the case of particle beams and lasers even sensors will not, in the first case because there is no radiation emitted, in the latter because the beam is travelling at the speed of light. Missiles and projectiles might be seen, but not by the human eye due to their probable velocities. In a written work this is easy to accommodate and while a visual work might have more trouble many weapons can be given a muzzle flash or other effect to show that they have fired, and energy weapons can have radiators that begin to glow(although visible glowing radiators are in themselves unrealistic). The bigger problem is that without visible weapons fire it may be difficult to convey to the viewer what the individual spacecraft are shooting at.

Explosions & Damage
One of the most dramatic moments in a space battle is when a spaceship with 'the good guys' aboard takes a hit. In most franchises this results in a big gout of orange fire and then, if we're lucky, a shot of the hull plating torn away from the support structure underneath, preferably glowing from the energy of the shot. This same ball of improbable fire makes its appearance when a spaceship, missile, or asteroid is blown up, and often on the detonation of nuclear weapons.

The problem with this is that high energy explosives use in warheads do not produce an orange fireball like an exploding car. Normal high explosives usually produce a nearly invisible blast since it is thermal energy that creates the visible fireball, and most explosive warheads are optimised to produce mechanical damage. A thermobaric warhead would create a nice gout of flame, but they are fundamentally unless in space. The explosion of fuel stores, the ignition of leaking atmosphere, and the release of superheated coolant can be used to explain these gouts of flame to some extent, but even then the effect will be far more rapid than inside an atmosphere, becoming more of a flash than a ball of fire. And even if something aboard the targeted vessel is ignited there will be no billowing smoke clouds, since these too will expand extremely rapidly in the vacuum of space.

High energy weapons such as lasers, particle beams, nuclear warheads, and possible plasma cannon, might leave glowing areas on the armour of a spaceship. I don't have the knowledge to judge on that. I do know that they will not produce big orange fireballs, though. High powered weapons strikes are going to be a bright flash of light, potentially coloured depending on the materials and weapons involved, with mechanical deformation affecting the surrounding area to some extent. The extent of the damage and its appearance is quite a complex question, and the best place to get answers is over on Atomic Rockets.

Related to this is the explosive end of every ship damaged in battle, usually with a nice fireball. Given the penetrative qualities of kinetic weapons, and the soft kill potential of radiation based weapons, it seems likely that many ships could be put out of action with very little exterior damage, at least in the case of larger ships. Given that real fusion and fission reactors are likely to explode the only explanation is that it is a result of high energy reactors of other kinds loosing containment. Certainly in Star Trek with their antimatter warp cores even an small but penetrating hit could cause a massive explosion. From a historical perspective it was easier to add a fireball back when CGI was in its infancy that it was to do complex battle damage, so that is the reason why it is so common in older works; newer works just continuing the trend for the most part.

Anything nuclear is usually surrounded by a lot of inaccuracies in any fiction, so it is no surprise that many works do not show nuclear explosions the way they should. In space, without an atmosphere to produce a fireball nuclear explosions will be very very brief, albeit of great intensity. Of course the afterimage would last much longer if you did see it in person. Often in movies and games nuclear explosions, even when they do not produce fireballs, persist for quite a while; in the real world you would blink and miss it.

The final inaccuracy commonly found alongside dramatic explosions is that nearby spacecraft will shudder as though hit by a blast wave; yet this is impossible without an atmosphere. The total mass left behind by an exploding missile, or even a ship, is insignificant compared to the volume of space, and unless the other spacecraft is ridiculously close, or shrapnel is involved, this is not going to happen.

None of the above are significant problems. They are mostly matters of convenience, of limitations in the medium used to depict that battle, or of convention. There is no particular trick to incorporating the 'correct' version of space battle visuals, but it does seem to be somewhat uncommon. I suspect that it is largely a result of the saturation of Star Wars and Star Trek; people are inspired by these franchises to create their own SF but often end up with a variation, rather than something that makes more sense on the world-building side. This is kind of like the ridiculous size of many spacecraft in SF, everyone else is doing it, so there is a temptation to use the exist metric rather than try to make the viewer use your universes internal scale or logic.

Tuesday, 15 March 2016

The Future is Shiny
One of the most futuristic aspects of Star Trek have been the iconic coloured displays and control panels. There are the large wall mounted MSDs or Master Systems Displays; a cross-section of the ship festooned with status data. Smaller panels cover the walls in Engineering and the Bridge, their bold visual style mimicked by the touch-sensitive controls consoles. They look sleek and futuristic, conveying information in a clean and uncluttered interface while offering the intuitive interaction of a touchscreen device. Compared to the infestation of switches, buttons, and lights in Star Wars, Battlestar Galactica, Firefly, and Alien/Aliens it is positively futuristic even to a modern audience. But is it as good as it looks?

The conflict between the attempt to portray futuristic technology and the practicalities of real life is a bitter one. Quite often the decisions are based around aesthetics rather than logic or practicality. I'm going to look at a few of the common elements of futuristic Science Fiction that bother me the most.

Touch Screen Controls

Star Trek's touchscreen tech might look cool, but they score somewhat lower on the practicality side. While the interface allowed by touchscreen can be far more intuitive and easy to use than a keyboard or button based system they become almost impossible to use in an erratically moving vehicle. Try typing a text message on a iPhone while riding cross country in a speeding jeep, or in a aircraft in a dogfight, or a fast boat, or a spaceship dodging or being hit by weapons fire. Especially on a spacecraft or in a military situation you don't want to hit the wrong command - it could be the difference between life and death. This is why modern military vehicles, particularly aircraft, may have touch screens but depend mostly on buttons. Buttons also cope fine with gloved hands, something that many touchscreen have issues with. Buttons and switches can also be used by touch in the dark, and with the latter can tell the user what is on or off without any light at all. No light conditions aren't much of an issue for civilians but are quite a concern for any military or organisation operating in a hazardous environment. While touchscreen will be ever-present in the technology of the future buttons will be right alongside them.

Transparent Holographic Screens
Holograms are cool. Projected onto a sheet of glass like the hud display of a fighter jet or floating in mid air they are one of the best ways to turn a simple computer screen into a signpost for the future. They are very common in modern SF, both written and visual, although it is with the latter that I have a bone to pick. To understand the limitations of a holographic display it is best to look at the most common application in current times, the HUD of a fighter jet. This allows the pilot to see vital information without distracting himself by looking down at instruments in the cockpit, keeping his eyes on the target at all times. Anyone who has played a FPS like Halo will understand the concepts use on a personal scale, as will anyone who has played a futuristic dogfighting game like Elite Dangerous. However the fact that allows this use - being mostly empty space - also makes them extremely impractical for a run of the mill monitor. Everything and anything behind the screen can become a distraction, or worse, make it difficult to read the data displayed by the hologram. Not only that but isn't having a colour-limited screen pretty useless? There is no way I know of that a hologram can produce a black background, and most are shown as monochromatic. Another issue is that of light. It is very easy to see holograms becoming difficult to read in bright light, and impossible if the light was on the opposite side to you. While they have the advantage of requiring no physical space this is only a minor one with the possibility of foldable screen technology in the future. So while I would not be surprise at the proliferation of hologram technology in applications such as compact devices, smart-glasses, and interactive 3D images they will supplement not replace conventional screens.

Sliding Pressure Doors
It is very rare to see a door in a Science Fiction movie that does not slide smoothly open at the tap of a button, the mere wave of a hand, or even without any invitation at all. That might not seem so bad, we have automatic doors all over the place after all. But a shopping centre is a sight different to a spaceship. Overlooking the frequent lack of obvious handles on the doors - how do you open them in a power out - there is still the fact that thy are the worst possible choice for a spacecraft. To be fair this only applies to doors expected to hold air pressure, but it is quite common to see the hatch of a airlock slide open, hiding itself away in the wall where it is utterly impossible to get to it if the power should fail or some other mechanical malady should occur. Of course we could just not be seeing the emergency manual controls, a handy lever or wheel hidden behind a panel on the wall perhaps. But there is a bigger problem. Any pressure differential is going to try and jam the door/hatch shut. Why? The pressure on the door will push it against the frame, creating greater than normal friction and possibly damage to the mechanism. Even if the motors are strong enough, and the mechanism but to withstand the stress is might make it impossible for a human to open in a power-out. The last point is not restricted to sliding doors; hinged doors should open onto the side expected to retain pressure so that the pressure holds the door shut rather than blowing it open. Sliding doors do have there uses. Restricted space, non-pressure critical locations, emergency doors with sharpened edges and hydraulics that can cut through debris to attain and airtight seal. It should also be noted that the larger the door the better a sliding door looks, as it does not need so much clear room to swing, and cannot slam shut as easily. But doors on which the atmospheric integrity of a spacecraft, space station, or indeed submarine depends probably should not be sliding. And yes, I shouldn't call it a door; hatch is probably the right term, but whatever.

Little details like these don't do much to make or break a work of SF, especially if it is a written one, or one that focuses on story rather than setting. But it would be nice to see more mainstream works(Hollywood movies) buck the trends in favour of something that while a little less shiny, is probably actually more futuristic. These are the three that have always irritated me; what are the technology tropes that bug you the most?

AddendumUniversal Computer Control

I somehow forgot all about this one, although it is one of the tropes that annoys me the most when it comes to Science Fiction. It is a well established thing in SF that AI has very high chance of going rogue and trying to kill all humans. One a spaceship this is a serious thing, as the engineers of the future seem to love putting all functions under the control of a shipboard AI. This is more reasonable in a military vessel, where the AI can continue to fight the ship even with numerous crew dead, but makes little sense in any other setting. Doors, for example, don't need to be AI controlled. Indeed, having simple systems like doors and lighting, along with the division of major systems like life support and thermal control, seems like a logical means of increasing redundancy. Not only does having seperate systems stop a hostile AI takeover or reduce its danger, but it gives better resilience to accidental damage or failure. Universal computer control also opens up the spacecraft for electronic warfare to a greater extent. In the Battlestar Galactica 'Verse the computer systems of Human ships were not networked ship-wide to prevent hacking by the Cylons from taking down all systems at once. So even when we have the ability to do so, I think it highly unlikely that we will turn over all control to a computer or AI system to the extent that is often seen in SF; there is no need, and a lot of possible dangers.

Monday, 1 February 2016

Wherever nerds Science Fiction fans gather to debate the future of space warfare there are several debates that almost always pop up sooner or later, and which seldom generate a consensus. One of the most popular is the debate over fixed Vs turreted weapon mounts, with the fixed weapons divided into spinal mounts, and less commonly broadside mounts. Related is the discussion over which of the three main direct fire weapons likely to be used in space combat - Laser, Particle Beam, and Kinetic - are most suited to each of the three mounting options. In this blogpost I'm going to attempt a analysis of the specific strengths and weaknesses of each type of mounting, which weapon fits them best, and the tactical scenarios in which they offer the biggest advantages. I'll also cover the worldbuilding needed to justify each option in your 'Verse.

The Spinal Mount

Definition: A weapon firing in a fixed forward arc, parallel to the direction of thrust, with limited elevation or traverse, and typically running through a significant portion of the spacecraft's length.

Spinal or Keel mounted weapons are interesting because, unlike turrets or fixed weapons, they have no current real-world counterpart aside from fighter aircraft. The sea going battleships that provide inspiration for many SF works used broadsides during the age of sail, and turrets in the era of Big Gun battleships, but a single forward firing weapon has never been used to my knowledge aside from a few submarines like the Surcouf, and that was neither common nor in line with the spinal mounts of SF. If anything their closest analogy is the main gun of a turretless tank hunter. Even that is a poor comparison given the role stealth plays in tank warfare, and the degree to which it is impossible in space.

The rational behind the Spinal Mount is straightforward and pretty logical; the bigger the gun the better, right? Most 'guns' in SF are in fact accelerators of some kind; railguns, coil-guns or gauss cannon, ram accelerators, and particle beams. What this means is that muzzle velocity scales directly with the length of the weapon, rather than their being a optimum barrel length as their is with conventional firearms. There are engineering limits, or those imposed by material science, but the highest theoretical velocity is as close to the speed of light as you can get. A Spinal mount also translates the power of the weapon to the audience quite easily, especially when coupled with long recharge times and/or cool down. The MAC guns of HALO and the Wave Motion Cannon of Space Battleship Yamato are pretty typical of this trope.

There are a few disadvantages with the spinal mount, most of which revolve around the fact that the spacecraft must manoeuvre to aim the weapon. Even if the finer adjustments are done internally rather than by the spacecraft's alignment it will still limit the speed that the spacecraft can edge widely separated targets. It also means that if a enemy emerged unexpectedly from hyperspace the spinal mount might not have time to be oriented before it is destroyed. Most spacecraft armed in this way are shown with only one main gun, with is a disadvantage if it breaks down or is disabled by enemy fire. The spinal mount might well be a glass cannon, extremely dangerous, but needing other ships to contribute to its defence, especially if under attack by multiple enemy.

While the time needed to aim, and the disadvantage of only being able to engage targets in the same direction at once are inescapable the problem of manoeuvrability may not be an issue. A spacecraft equipped with a powerful gauss cannon, railgun, particle beam, or laser, will have plentiful electric power. This can be used to power multiple thrusters distributed all over the spacecraft, rather than having them clumped together, and allowing acceleration in any direction. With many fictional spacecraft the main drives are to large, expensive, or radioactive to allow this, but for more realistic low accelerations electrothermal or plasma based drives may do fine.

The advantages are many. A spacecraft can fit a larger spinal weapon than it could hope to fit into a turret, something likely to hold true for any size of spacecraft. This is partially due to the fact that a turret has to turn, and so has limits on the mass and size of the weapon, and partially to the fact that recoil forces along the line of thrust can be absorbed by the thrust structure instead of by a complicated system of articulation. This can also make the weapon more accurate as it will not have to cope with the vibration of turret articulation, or the fox in a unsupported barrel. Greater muzzle velocity has the advantage of imparting a longer effective range on particle beam and kinetic weapons, helping to negate their inherent weakness. Even if the energy they output is the same as a physically smaller weapon, the increased range will make them more effective at ranged combat, something there is likely to be a lot of in space. And they do not need the cool down time shown in SF. The most powerful might, but it should not be a surprise to find MAC gun like weapon with rapid fire capabilities.

Kinetic weapons benefit the most from a spinal mount as opposed to a turret or broadside since it helps to overcome their greatest weakness - low velocity. Particle beams may also be common in this role since the long skinny shape of a particle accelerator fits the bill nicely. Lasers on the other hand do not seem to be a good candidate. Lasers do not benefit from having a longer physical shape, it is the diameter of the emitter that counts. While there is an analogue - a spacecraft with a single massive mirror at the front - it has its own advantages and disadvantages, and does not really fit the description of a classic spinal mount. Operationally it would be employed the same however, and have the advantage in rage over smaller turreted counterparts.

It is this range benefit coupled with the low turning rate that define the use of spinal weapons. They are the long ranged artillery of space. If they can maintain range from the enemy the extra range might make them well right invulnerable, while if used in a defensive role that extra reach will fore the enemy to run a gauntlet of fire. A battle between two of these spacecraft would be like a sniper duel - few tactics, with the one with the greatest accuracy coming out on top. They would be at a disadvantage in any battle where there are multiple vectors of attack, or one that starts at close range. In a battlefield dominated by missiles they might not fare to well, but one that focuses on direct fire is likely to see them.

The 'Verse that features spinal weapon can fall anywhere on the spectrum of scientific realism. Given their long range and potential firepower it seems likely that any space force will have some in its ranks, and that they will form an important part of tactical doctrine. One thing to note is that they become less attractive as the number and acceleration of ships increases as this brings out their weakness. A jump drive that allows enemy to 'slip under the guns' as it were will also compromise them. In any battle where missiles are unviable, massive firepower is needed from smaller ships, or the enemy will be engaged at extreme range a spinal mount is justified. Another thing to remember is that a magnetic accelerator could be developed as a civilian cargo launcher on the moon, and repurposed as a weapon during a war, similar to in Heinlein's The Moon is a Harsh Mistress. Even particle beams or lasers that fit the design requirements might be developed as part of beamed power stations.

The TurretDefinition: A weapon or weapons mounted on or in an articulation that provides extreme ranges of traverse and elevation, as well as commonly housing the firing/loading mechanism and gun crew.

The turret is one of the most common styles of weapon mounting in SF, and for good reason. Nearly all wet navy guns are mounted in turrets, as are point defence weapons, and the main gun of tanks. It was the invention and adoption of turreted main guns, along with the invention of the steam engine, that changed the face of ocean warfare forever. A spacecraft armed with turrets can bring more of its weapons to bare on any enemy craft, and can do so regardless of its heading. This is obviously important in a battle involving many spacecraft in close proximity, especially those capable of fairly pronounced manoeuvres and high acceleration. Point defence weapons are far far more effective will a turret mount than without, allowing them to track incoming.

There are two common mistakes with the representation of turrets in SF. The first is the idea of a turret as a bolt on unit. While this may be the case for smaller point defence units, it is almost never true of larger weapons. Even the small gun turrets wet navy ships still use extend below the deck level, and old battleship turrets had more concealed than exposed. The second issue is when turrets are placed in a position where the firing arc is limited by other turrets or by the hull of the spacecraft. While the latter is to an extent unavoidable the former defeats the purpose of having a turret to begin with. Yes, I'm looking at you Star Wars.

Disadvantages of the turret are simple. For any given weapon a turret to carry it will add complexity, mass, and power requirements to the design of the combat spacecraft, reducing the overall number that can be carried and increasing the cost. Reduced accuracy can also be a problem due to vibration from the traverse motors, increased vibration in the flexible bearings, and flex in a unsupported barrel. There amy also be a limit to the ammo that can fit in the turret, decreasing the overall firing rate. Unique to spacecraft is the problem that recoil forces imparted on the spacecraft are not going to be constant, and will thus be harder to account for as they impact the trajectory of the whole craft.
Fundamentally turrets have a single advantage; they can be aimed independently of the spacecraft's orientation. All the other advantages - reduction in number of guns needed to provide coverage in terms of point defence, ability to engage multiple targets in different directions etc are all derived from the former. The advantage is most pronounced with point defence weapons, as they will face threats from many angles, and need to be able to track fast and close targets.

Kinetic weapons are ideal for turrets given that unguided kinetics have short ranges, and it is in this envelope that turrets offer the biggest advantage. Lasers also have a lot going for them. Since the laser itself is likely to be in the main hull rather than the turret itself, with the beam reflected through a series of mirrors, there can actually be more turrets than the spacecraft can generate laser light for. Whichever turrets are needed have laser directed into them, and the loss of a few to enemy fire is not such a disadvantage since the total energy output does not decrease. Particle beams benefit the least. This is both due tho their long skinny shape in most designs, and to the fact that bending a particle beam at any kind of angle will produce synchrotron radiation. Tis could of course be overcome by having truely massive turrets or miniaturised particle beams. In terms of point defence lasers are likely to be dominant given their accuracy at range, and the fact that a missile probably won't be too well armoured compared to a spacecraft. Adaptive optics can also give point defence turrets quicker focusing and greater accuracy. Kinetic point defence will be regulated to slower firing 'flak guns' that throw up a wall of shrapnel rather than targeting individual threats.

Unlike broadside and spinal mounts turrets have the best chance of dominance in a softer SF 'Verse. This is because they are best suited to short ranged, high relative speed combat where aim will have to be shifted quickly, and the spacecraft will be changing direction often. They are also suited to battles where enemy spacecraft can emerge unexpectedly from hyperspace in any direction, and in which the spacecraft of both sides end up occupying the same volume of space. Obviously force fields or shields help in this regard as they encourage ships to close to kinetic range where they can output more damage. In a hard science 'Verse close quarters battles are unlikely as everyone will be seen long before they get into range, and with the ranges that are more realistic decrease the disadvantage of fixed weapons and emphasise range and accuracy. Turrets will always be used as point defence installations however, so they will never be absent. A lot of works also feature turret mounted kinetic guns as secondary weapons, like the Sulaco from Aliens; this is quite likly considering the relatively small size that kinetic weapons can have while remaining potent enough to be included.

The BroadsideDefinition: Weapons mounted at right angles to the direction of thrust, usually within the main hull of the spacecraft, and with limited traverse and elevation.
A fixed broadside battery is one of the most uncommon arrangements to be seen in SF, with turrets being far more common. The only one that I can think of in visual SF is the gun deck aboard the Separatist ship at the beginning of Revenge of the Sith. In written works the Black Fleet Trilogy by Joshua Dalzelle had what sounded like a fixed battery of laser weapons on the ship that acts as the setting for most of the first book, but it was never implicitly stated. In the Honor Harrington books the beam weapons were, by memory, in broadside arrangement; a necessity imposed by the gravity drives used. There are also the quite common examples in visual media where turrets are shown that would be unable to fire in any arc except that of a broadside. Most of the turreted guns seen in the Star Wars movies fall into this category, with the Venator Class being a prime example.

The scarcity of this arrangement is not unexpected. With the prevalence of the 'Space is a Ocean' trope it is to be expected that a design philosophy that long ago gave way to turret armament should find little traction. Where it is found it is most often for the visual effect, or because the work is intentionally trying to mimic the battles of the Napoleonic War transposed into space.

There are not so many advantages to this type of design, and the conditions under which it become practicable are quite specific. The main advantages are those shared by any fixed weapon mount. Each weapon will mass less than an equivalent turret, and be simpler in construction. It may be more accurate since it can be mounts straight to the spacecraft's structure via recoil absorbing mechanisms, reducing vibration. Ease of access would also be a big factor, especially with advanced and perhaps temperamental weapons since turrets have never been known as spacious. The weapon itself might also be more massive than a turret could cope with, or have a larger recoil force.

Disadvantages are pretty obvious. Limited traverse and elevation impose a greater need for manoeuvrability on the spacecraft, and run the risk that at close range or high traverse speed a more manoeuvrable target could stay out of the fire arc entirely. This is partially avoided with lasers, since with adaptive optics they can have quite a good arc of fire without the actual emitter being articulated. Since they cannot fire forward the spacecraft is at a disadvantage accelerating toward or away from a target, although this may not be a problem depending on the technology level of the 'Verse. The broadside, and all fixed weapons, are at a disadvantage in a 'Verse where FTL can allow a enemy spacecraft to appear unexpectedly in any direction. The need to rotate the entire spacecraft is going to slow down response times significantly compared to a turreted vessel. Conversely the broadside is more attractive in a hard science 'Verse where you will always see the enemy coming.

A broadside thus falls best into a 'Verse with fairly low accelerations and long engagement ranges. It also becomes a lot more practical if the main offensive weapon is a missile attack from standoff range, especially if it is one involving tens or hundreds of missiles, and possible submunitions. The ability to carry more weapons for the same mass than in turrets, coupled with the greater accuracy and potentially greater effective range would give the broadside ship a very good defence against missile spam attacks. Against such an attack it is the volume, range, and accuracy of defensive fire that will stop your spacecraft from being ventilated by a hypervelocity penetrator, and in this regard the broadside holds the advantage. Also, the greater the number of weapons, the more incoming can be targeted at once.

Lasers or kinetic weapons would be the most practical. Lasers would benefit from having many emitters, allowing more incoming to be targeted at once, and for kinetics it allows a greater overall rate of fire, important given their inaccuracy. With kinetics it could also extend their offensive range by filling more space with metal than would be possible with fewer weapons and making it difficult to evade with low thrust levels; range would still be terrible compared to other weapons however. Charged particle beams could interfere with each other, but a neutral beam wouldn't ave that issue. The soft-kill ability of a particle beam might also prove handy against missile attacks; the beams could even be defocused to fill a huge volume of space with relativistic plasma, providing a potent radiation hazard for any incoming missiles. But without exact numbers it seems impossible to give any of the three weapon types a clear advantage for broadside use; it depends doll on the details of the setting.

Some of you might object to the idea that lasers are better with many emitters, and it is a common debate. Do you use one emitter with longer range, or many smaller? My reasoning is that in a 'Verse where missiles are a viable main offensive weapon they will broadly be able to fire enough missiles with enough submunitions that the extra range is not such a great advantage, more so since a accelerating missile at a half a light second or so is going to be phenomenally hard to hit, and could be travelling at a huge speed by that time. In any case, a computer controlled array of smaller emitters can act as a single larger emitter to some extent, in the same way as many modern telescopes use mirrors composed of multiple segments.

Although not strictly a 'broadside' a missile armed spacecraft might have its storage silos arranged in the same configuration to allow more rapid deployment. With warfare based on missile spam the ability to unleash more missiles in less time might be the best chance at victory, and having the equivalent of a current VLS(Vertical Launch System) might be the ideal. This could also look pretty cool visually while maintaining realism, so take notice Hollywood!

Well, there we go. Part 3 is in the works, but no promises on how long it will take. Anyone interested in a deeper discussion of this topic, along with the maths, can find a wealth of info on the Atomic Rockets website. There is a lot there though, so this may be more helpful to someone looking at a overview of the subject.

Friday, 22 January 2016

NOTE
I originally wrote this post as a guest post for the Future War Stories blog( link), where it generated a lot of very interesting discussion in the comments. Since then, and mainly as a result of the comments, I've decided to expand on the theme of tactical manoeuvres. I'm posting this so that anyone reading either part will be able to find the other; I do encourage reading the comments on Future War Stories though, they have almost as much stuff as the post itself.

Hopefully this will develop into an extended series of posts, some of which will be design related like my Building a Space Battleship, and some will be looking at tactics, strategy, etc.

SF Worldbuilding has been on a bit of a hiatus, but I'm going to be posting again, hopefully. I remember saying that before though, so don't get to excited. If anyone has any ideas for non-military future tech they'd like a post on please leave a comment; my main interest is military SF, so I find other things hard to think of, but want the blog to have a broader scope than that.

"I am a leaf on the wind" - Wash

The hand can't hit what the eye can't see
As both 'Wash' Hoban(Firefly) and Han Solo(Star Wars) have demonstrated on numerous occasions firepower is not the only asset that can win a fight. Quite often in movie SF the heroes of the story will be aboard a smaller spacecraft than their opponents, their only hope of survival lying in their superior abilities. While this is largely due to dramatic reasons, it does draw attention to the importance of manoeuvrability in space combat. When dealing with hard SF - no handwavium forcefields or technobabble shields - one shot kills are very probable: nukes, mass drivers, particle beams, lasers, all posses more than enough potential to negate any form of armour we know about today. And while no real spaceship will every fly with the grace of a X-wing starfighter this does mean that the ability to avoid hits may be more important than surviving them(structurally, the crew is still a concern), much like the situation in arial combat today.

For SF writers this is a boon. A battle that requires manoeuvres is intrinsically better suited to one in which humans might play a role. Randomness and intuition could be vital, and so far computers don't offer that. Even if the ship can fly and fight itself this leaves room for a human tactician, negating Burnside's Zeroth Law of Space Combat - SF fans relate more to humans than they do to silicon chips. However, it can also pose difficulties. Space is not a familiar environment, and movement in it is counterintuitive at best. It is also radically different for a spacecraft in orbit around a single planet, in a planetary system, or in deep space. And for those of us who try to avoid the dreaded 'Space is a Ocean' trope this can be very...frustrating.

So, I'll look at four basic situations; deep space with low relative velocity, deep space with high relative velocity, single planet, and planetary system. For each I'll also take a look at the changes in the situation that different tech will have. This post is not so much about manoeuvring itself, but about how different situations shape it. An in depth discussion of tactical manoeuvring down to the level of orbital physics or specific technologies would make the article far to long. In the future I'll attempt to do follow up articles that look at manoeuvring in the context of a specific spacecraft, but for now this should provide an indication of what a spaceship would be doing. For simplicity's sake I'm only going to consider one-on-one battles in detail, not constellation engagements. Fleet actions are a whole separate ball game, and will warrant a separate post.

Deep Space - low relative velocity
Just what is 'deep space'? For the purposes of a story it is that area of space which only the bigger spacecraft can reach, so interplanetary or interstellar, depending on tech levels. From a navigational perspective it could be defined as 'flat' space. That is, space in which the gravitational acceleration is insignificant. Insignificant is defined by the power of the drives your spacecraft is using, so this adjusts itself to match the setting.
Manoeuvres here are closest they will get to those found in Space Opera. The lack of a gravitational source means that movement in any direction is equally easy, and the fight becomes truly 3D.
For high tech - multi-gee acceleration and big delta-V - the fights will be 'dogfights' to some degree. This will be more marked if the craft use spinal mounted weapons, or if they have large blind spots in offensive or defensive weaponry. If kinetics are the main weapon then the fight could become quite interesting, with KE rounds restricting the possible choices for manoeuvring, a possible tactic for the adept captain to employ. Missiles will be very effective, with s straight line of flight to the target, as will beam weapons. Particle beams will benefit, as they are degraded in accuracy and rage in the presence of a planet's gravity or magnetic field. If lasers are the primary weapon then the fight will be less of a dogfight, and more of random 'drunk-walking' to throw off targeting.
For low tech - milligee acceleration and limited delta-V - visually this would be quite boring. The ships cannot perform elaborate manoeuvres to get in each other's blind spots, nor can they expect to dodge beams and kinetic weapons at short ranges(ranges dependant on velocity of the weapon). Instead orientation and sensor data is the most vital. The spaceship must bring the most weapons to bear, while at the same time keeping a small target profile, and reducing signals that might give its opponent an effective targeting solution. The ships orient themselves, enter weapons range, fire a few salvoes, and the battle is decided. In this case missiles are very effective, as they can come in at an angle to the primary attack vector, distracting sensors and absorbing point defence capacity. Kinetic rounds are also more effective, not only can the score a hit from longer range, but they can be more easily used to 'box in' an opponent than if accelerations were high. As before, 'drunk-walk' will be used to throw off targeting.

Deep Space - high relative velocity
The chances are that spaceships will rarely intercept each other in deep space. It is simply to large, and too easy to see someone coming. When they do it is likely to be a head-on pass at high relative velocity for two spacecraft following the same or similar orbit in opposite directions. Note that once unrealistically powerful torch-drives become common, interception is possible, if still unlikely unless both parties wish it, or one slips up.
It turns out that for both high and low tech the manoeuvres are much the same in this situation. Any reasonably fast orbit will result in the two ships passing with Rv of tens if not hundreds of km/s. At this speed there is not time to dogfight. Even a torch ship, which will have a much higher intercept velocity, will take so long to cancel its Rv and return to the battle it would be considered as a separate engagement, rather than a second pass. For a ship with foreseeable tech it would be nearly impossible. If anything it will resemble a joust between two medieval knights on horseback. Unlike a joust, however, they might not be a winner.
The longest commonly accepted range for a laser weapon to target effectively is about one light second, or 3*10^8 meters. At a very low end relative velocity - I randomly chose 40 km/s, which means that each ship has ~half solar escape velocity, which is not unrealistic, nor is it that high for a advanced ship. At this range and closing speed the time for targeting the incoming ships and its projectiles is ~2 hours. Plenty of time to shoot down incoming projectiles, you say. But at this speed one kilogram of inert matter has an energy of 8*10^8 J. And how many of those is the opposing ship going to throw out in your path? You can make considerable sideways movement relative to direction of travel in an effort to avoid the projectiles, but the opposing ship can easily see any move you make, and at charter ranges dodging will become impossible. Pretty much any kinetic hit at this speed will be fatal, so it will be the ship with the best point defence, sensors, and emergency manoeuvring that will survive.
Durin the approach both ships fill space with inert projectiles, possible with last ditch terminal guidance. They will be hard to spot at long range, tiny, inert, and possibly cooled down so that they have no discernible thermal signature. So it will be only in the last stage of the pass that the combatants can begin to dodge the projectiles. High lateral acceleration and powerful attitude control will help to weave through the incoming fire like a skier on a slalom course. Good sensors will be needed to sport the incoming, and good PD to shoot those that can't be avoided. However, it is my personal opinion that this sort of situation would be 'two men go in, half a man comes out'. If energy wagons are primarily used, them this is even more so the case, as dodging becomes effectively impossible.

Orbital Space - single planet
Most space battles in SF take place in orbit around a planet. This makes sense in both hard and soft SF 'Verse's for several reasons. Primarily it is the place where hostile spacecraft are most likely to meet. It also adds a new layer of complexity to the fight, introducing 'terrain' to the tactical considerations. The planet can hide opponents, restricts manoeuvres, sucks up delta-V, and provides something to crash into.
Aside from hiding spacecraft who are on the other side a planet can slo provide some cover for combatants. Picking up a spacecraft against the disk of a planet is significantly harder than spotting one against the backdrop of space after all. A low orbit that brushed the atmosphere prevents opponents from attacking from most of one hemisphere, a great advantage. For a craft equipped to reenter the atmosphere it also offers the possibility of manoeuvres not possible with the amount of delta-V they posses. From reading Atomic Rockets kinetic weapons seem to hold the advantage shooting from a higher orbit at a lower. A DEW is not effected so much, and so the orbit used is less of an advantage or disadvantage aside from the detection aspects. Lasers also posses the potential to be 'bounced' around the horizon by remote drones, meaning that the attacker can shoot without exposing themselves.
So the aim of any manoeuvres is pretty simple. Orientation to bring weapons to bear, and the standard 'drunk-walk' are a given. The opposing captains will try to gain the better position in an orbit underneath the enemy ship, or perhaps between the enemy ship and the sun, which might help to blind sensors. This will be complicated by the fact that change orbital inclination is very hard compared to other manoeuvres, restricting the spacecraft to a 3D layer of space, although not 2D plane shown in so many soft SF works. Forcing the ship into a lower orbit will decrease its orbital period, and vice versa. Combined with changing the orbit from circular to the elliptic and back this gives spacecraft commanders the ability to surprise their opponents by appearing around the planet at a different place or time than expected. There will also be a large amount of 'minelaying' of a kind, seeding or its will kinetic projectiles in order to herd the enemy into a bad position.
But while the aim of the manoeuvres is simple, execution is not. Trying to explain it is beyond me, so I suggest that anyone serious about grasping orbital mechanics begins by playing the Kerbal Space Program game, or browsing youtube for anything helpful. It makes a lot more sense visually than it ever will in writing. High tech - for advanced ships a planet is a much smaller piece of terrain, a hill rather than a mountain. They can more easily afford to change orbits, to drop below minimum orbit al velocity or go over the maximum, and can perform delta-V heavy manoeuvres such as change the orbital inclination. The ultimate of course is a ship that has drives powerful enough to reverse its orbit completely, surprising its opponent when it emerges around the opposite side of the planet to what was expected. With higher acceleration and delta-V the seeding of orbits becomes less effective, much easier to dodge than with a low powered spacecraft. Low tech - with low levels of acceleration, even if the spacecraft has a high delta-V, changing orbits can take days if not weeks. The position of the enemy will be highly predictable, and so kinetic weapons become very important. The advantage converted by different orbits will be much more apparent, as it is harder for anyone to turn the tables on their opponent. Most tactics would be a combination of manoeuvring into a good position, and using kinetics to force the enemy into a bad one. Low tech ships would also gain a large advantage by being able to dip into the atmosphere, as this provides essentially free deceleration, saving reaction mass.

Orbital spaghetti

Planetary Systems

Adding more heavenly bodies to the mix vastly increases the tactical possibilities. While 'planets' per se do not do much, moons do. A gas giant with seven or eight moons is a extremely complicated system, and has travel times of only hours or days as opposed to years between planets, and that is with Hohmann orbits. High acceleration, low delta-V spacecraft could follow complicated routes, sling-shoting themselves around the moons to gain an unexpected position. For much of the time they could be out of sight of the enemy, making it a scenario reminiscent of The Hunt for Red October. The fact that moons often have lower gravity than planets also means that the manoeuvres in proximity to them can be more extreme given the same tech level. It even brings up the possibility of landing on a moon, camouflaging the spacecraft, waiting for the enemy to pass by, and then launching and taking them by surprise. The changes imposed by tech levels are the same as those for a single planet, so I won't both to go into detail. This kind of setting will be the most complicated for a SF aficionado to get right, and I would suggest finding a solar system simulator to model the setting before attempting to figure out a complicated battle. It does lend itself to far more interesting scenarios, however, and will be far more rewarding.